/*
 * Copyright 2012 The Netty Project
 *
 * The Netty Project licenses this file to you under the Apache License,
 * version 2.0 (the "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at:
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */
package io.netty.channel.group;

import io.netty.channel.Channel;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelFutureListener;
import io.netty.util.concurrent.BlockingOperationException;
import io.netty.util.concurrent.DefaultPromise;
import io.netty.util.concurrent.EventExecutor;
import io.netty.util.concurrent.Future;
import io.netty.util.concurrent.GenericFutureListener;
import io.netty.util.concurrent.ImmediateEventExecutor;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

/**
 * The default {@link ChannelGroupFuture} implementation.
 */
final class DefaultChannelGroupFuture extends DefaultPromise<Void>
        implements ChannelGroupFuture
{

    private final ChannelGroup group;

    private final Map<Channel, ChannelFuture> futures;

    private int successCount;

    private int failureCount;

    private final ChannelFutureListener childListener = new ChannelFutureListener()
    {
        @Override
        public void operationComplete(ChannelFuture future) throws Exception
        {
            boolean success = future.isSuccess();
            boolean callSetDone;
            synchronized (DefaultChannelGroupFuture.this)
            {
                if (success)
                {
                    successCount++;
                }
                else
                {
                    failureCount++;
                }

                callSetDone = successCount + failureCount == futures.size();
                assert successCount + failureCount <= futures.size();
            }

            if (callSetDone)
            {
                if (failureCount > 0)
                {
                    List<Map.Entry<Channel, Throwable>> failed = new ArrayList<Map.Entry<Channel, Throwable>>(
                            failureCount);
                    for (ChannelFuture f : futures.values())
                    {
                        if (!f.isSuccess())
                        {
                            failed.add(new DefaultEntry<Channel, Throwable>(
                                    f.channel(), f.cause()));
                        }
                    }
                    setFailure0(new ChannelGroupException(failed));
                }
                else
                {
                    setSuccess0();
                }
            }
        }
    };

    /**
     * Creates a new instance.
     */
    DefaultChannelGroupFuture(ChannelGroup group,
            Collection<ChannelFuture> futures, EventExecutor executor)
    {
        super(executor);
        if (group == null)
        {
            throw new NullPointerException("group");
        }
        if (futures == null)
        {
            throw new NullPointerException("futures");
        }

        this.group = group;

        Map<Channel, ChannelFuture> futureMap = new LinkedHashMap<Channel, ChannelFuture>();
        for (ChannelFuture f : futures)
        {
            futureMap.put(f.channel(), f);
        }

        this.futures = Collections.unmodifiableMap(futureMap);

        for (ChannelFuture f : this.futures.values())
        {
            f.addListener(childListener);
        }

        // Done on arrival?
        if (this.futures.isEmpty())
        {
            setSuccess0();
        }
    }

    DefaultChannelGroupFuture(ChannelGroup group,
            Map<Channel, ChannelFuture> futures, EventExecutor executor)
    {
        super(executor);
        this.group = group;
        this.futures = Collections.unmodifiableMap(futures);
        for (ChannelFuture f : this.futures.values())
        {
            f.addListener(childListener);
        }

        // Done on arrival?
        if (this.futures.isEmpty())
        {
            setSuccess0();
        }
    }

    @Override
    public ChannelGroup group()
    {
        return group;
    }

    @Override
    public ChannelFuture find(Channel channel)
    {
        return futures.get(channel);
    }

    @Override
    public Iterator<ChannelFuture> iterator()
    {
        return futures.values().iterator();
    }

    @Override
    public synchronized boolean isPartialSuccess()
    {
        return successCount != 0 && successCount != futures.size();
    }

    @Override
    public synchronized boolean isPartialFailure()
    {
        return failureCount != 0 && failureCount != futures.size();
    }

    @Override
    public DefaultChannelGroupFuture addListener(
            GenericFutureListener<? extends Future<? super Void>> listener)
    {
        super.addListener(listener);
        return this;
    }

    @Override
    public DefaultChannelGroupFuture addListeners(
            GenericFutureListener<? extends Future<? super Void>>... listeners)
    {
        super.addListeners(listeners);
        return this;
    }

    @Override
    public DefaultChannelGroupFuture removeListener(
            GenericFutureListener<? extends Future<? super Void>> listener)
    {
        super.removeListener(listener);
        return this;
    }

    @Override
    public DefaultChannelGroupFuture removeListeners(
            GenericFutureListener<? extends Future<? super Void>>... listeners)
    {
        super.removeListeners(listeners);
        return this;
    }

    @Override
    public DefaultChannelGroupFuture await() throws InterruptedException
    {
        super.await();
        return this;
    }

    @Override
    public DefaultChannelGroupFuture awaitUninterruptibly()
    {
        super.awaitUninterruptibly();
        return this;
    }

    @Override
    public DefaultChannelGroupFuture syncUninterruptibly()
    {
        super.syncUninterruptibly();
        return this;
    }

    @Override
    public DefaultChannelGroupFuture sync() throws InterruptedException
    {
        super.sync();
        return this;
    }

    @Override
    public ChannelGroupException cause()
    {
        return (ChannelGroupException) super.cause();
    }

    private void setSuccess0()
    {
        super.setSuccess(null);
    }

    private void setFailure0(ChannelGroupException cause)
    {
        super.setFailure(cause);
    }

    @Override
    public DefaultChannelGroupFuture setSuccess(Void result)
    {
        throw new IllegalStateException();
    }

    @Override
    public boolean trySuccess(Void result)
    {
        throw new IllegalStateException();
    }

    @Override
    public DefaultChannelGroupFuture setFailure(Throwable cause)
    {
        throw new IllegalStateException();
    }

    @Override
    public boolean tryFailure(Throwable cause)
    {
        throw new IllegalStateException();
    }

    @Override
    protected void checkDeadLock()
    {
        EventExecutor e = executor();
        if (e != null && e != ImmediateEventExecutor.INSTANCE
                && e.inEventLoop())
        {
            throw new BlockingOperationException();
        }
    }

    private static final class DefaultEntry<K, V> implements Map.Entry<K, V>
    {
        private final K key;

        private final V value;

        DefaultEntry(K key, V value)
        {
            this.key = key;
            this.value = value;
        }

        @Override
        public K getKey()
        {
            return key;
        }

        @Override
        public V getValue()
        {
            return value;
        }

        @Override
        public V setValue(V value)
        {
            throw new UnsupportedOperationException("read-only");
        }
    }
}
